Recently, a compact disk, a laser disk and so on have been used as data storage apparatuses for storing video and audio data, etc. In data storage apparatuses which use such disks, data is recorded in pits each of which has a constant width in the direction of tracks which are concentrically formed on the disk. The disk player using such disks irradiates a laser beam to the pit, detects any variation of the reflected laser beam, and reads the data recorded on the disk to perform a reproduction operation. Regions of the disk are divided into a lead-in region, a program region and a lead-out region. Table of contents (TOC) data is recorded in the lead-in region. The record data, for example, a control signal (such as "during-music," "inter-music," "music number," "running play time," etc., in the case of audio recordings) is recorded in the program region, together with the audio or video data signals. A control signal which represents the end of the play is recorded in the lead-out region.
As compact disks and laser disks are of differing diameters, to check whether a compact disk is loaded onto the compact disk player, a focus-on point and a limit switch-on point are both established at the same location. However, for laser disks, the above two points are respectively established as different locations on the disk. That is, FIG. 1 shows the locations of the focus-on point and the limit switch-on point on a laser disk 10, in which reference numeral 2 denotes the focus-on point and reference numeral 3 denotes the point where the limit switch is turned on. The focus-on point and the limit switch-on point are different from each other in order to discriminate the type (compact disk versus laser disk) of the loaded disk in a reproducing apparatus which uses both types of disks. Here, the focus-on point of the laser disk is located outside of the lead-out region of the compact disk.
To check if laser disk 10 of FIG. 1 is loaded when power is applied, the conventional lead-in operation performed in the laser disk reproducing apparatus for laser disks having the above structure is made to transfer a pick-up (not shown) to focus-on point 2 thereby completing the focussing operation.
In this case, if the focussing is not completed, it is determined that the laser disk 10 is not loaded. In the case of a reproducing apparatus which commonly uses a compact disk as described above, the pick-up (not shown) is moved to a focus-on point corresponding to the compact disk, to again make an attempt at focussing. However, in the case of a reproducing apparatus for use only with laser disks, the reproducing apparatus is set to a standby mode until the laser disk is loaded.
On the other hand, if the above focussing is completed, a spindle motor (not shown) is driven, the pick-up (not shown) jumps the track of the laser disk which rotates according to the drive of the spindle motor, to move the pick-up to the above limit switch-on point. Then, when the picku-up reaches the switch-on point, the lead-in region on which the disk condition information is loaded is read out.
As described above, the spindle motor is driven so that the pick-up reaches the limit switch-on point after the focussing is completed, and the pick-up is moved while the tracking is controlled so that a track-jumping operation is performed by the use of an objective lens. Accordingly, the required lead-in time (completed before searching the location of the program to be reproduced and after the focussing is completed) is equal to the time needed for performing the above-described operation.